Guide apparatus for a turbine of an exhaust gas turbocharger

ABSTRACT

In a guide apparatus for a turbine of an exhaust gas turbocharger with a first insert part and a second insert part arranged opposite the first insert part and with at least one first guide vane for deflecting exhaust gas flowing through the turbine, which is arranged between the insert parts and rotatably supported on at least one of the insert parts so as to be rotatable about an axis of rotation relative to the insert parts, at least one second guide vane for deflecting the exhaust gas is provided which is immovable relative to the insert parts.

This is a Continuation-In-Part application of pending international patent application PCT/EP2013/000020 filed 2013 Jan. 8 and claiming the priority of German patent application 10 2012 001 236.5 filed 2012 Jan. 18.

BACKGROUND OF THE INVENTION

The invention relates to a guide apparatus for a turbine of an exhaust gas turbocharger with an insert structure comprising first and second insert elements and a guide vane structure arranged between the insert elements and being pivotally supported on one of insert elements.

Such a guide apparatus is known from EP 2 226 484 A1. The guide apparatus is installed in a turbine casing of a turbine of an exhaust gas turbocharger with a first insert part being arranged in the axial direction of the turbine opposite a second insert part.

The guide apparatus comprises at least one first guide vane. The guide vane serves to deflect the exhaust gas flowing through the turbine so the exhaust gas may aerodynamically efficiently flow into a turbine wheel of the turbine, which is arranged downstream of the guide vane. The guide vane is arranged between the insert parts and supported on at least one of the insert parts so as to be rotatable about an axis of rotation relative to the insert parts. The rotatable guide vane creates a variable turbine geometry, so that the turbine may be adapted as required to different exhaust gas mass flows through the turbine.

It is the object of the present invention to provide a guide apparatus for a turbine of an exhaust gas turbocharger of the above mentioned type in such a manner that the guide apparatus allows a particularly efficient operation of the turbine.

In a guide apparatus for a turbine of an exhaust gas turbocharger comprising an insert element with a first insert part and a second insert part wherein the first insert part is arranged opposite the second insert part and the guide apparatus further comprises at least one first guide vane for deflecting the exhaust gas flowing through the turbine with the guide vane arranged between the insert parts and is supported on at least one of the insert parts so as to be rotatable about an axis of rotation relative to the insert parts, at least one second exhaust gas deflecting guide vane is provided, which is immovable relative to the insert parts, i. e. fixed.

Because the guide vane is fixed relative to the insert parts, no or only very small function gaps are provided or required, respectively, between the second guide vane and the insert parts. Therefore, flow losses, so-called secondary flow losses, may be prevented or minimized so that the second guide vane may deflect the exhaust gas flowing around the guide vane at least essentially completely in an aerodynamically efficient manner. This leads to an aerodynamically efficient flow into the turbine wheel of the turbine, which is arranged downstream of the guide vanes and brings about a particularly efficient operation of the turbine and thus of the exhaust gas turbocharger. This also brings about an efficient operation of a combustion engine associated with the turbine so that particularly low fuel consumption as well as low CO₂ emission are achieved.

In addition, the inventive guide apparatus facilitates by means of the first guide vane that the turbine may be adapted as required to different exhaust gas mass flows. For this purpose, the first guide vane is rotated about the axis of rotation relative to the insert parts, which is accompanied by a variation or an adjustment of the effective flow cross-section of the guide apparatus and thus of the turbine. In other words, by means of varying the first guide vane relative to the insert parts, the effective flow cross-section may be variably adjusted so that the turbine or its turbine wheel may be efficiently driven by the exhaust gas both for relatively small exhaust gas mass flows and comparably large exhaust gas mass flows.

In a particularly advantageous embodiment of the invention, at least one of the insert parts and the second guide vane are formed integrally with each other. It may be provided that at least one of the insert parts is formed of at least two interconnected insert segments, with one of the insert segments and the second guide vane being formed integrally with each other. Alternatively or additionally the second guide vane may be formed by at least two interconnected vane segments with one of the vanes segments being formed integrally with at least one of the insert parts or with one of the insert segments, respectively. Or half of the first guide vane may be formed integrally with the first insert and the other half with the second insert and the two inserts may be joined via the two guide vane halves.

It is also possible that at least one of the insert parts or both insert parts and the second guide vane are formed completely integrally with each other. The guide apparatus may therefore be manufactured rapidly and economically. Thereby, the guide apparatus also comprises a very low number of components so that it may be very easily and economically assembled and installed into a turbine casing of the turbine. Furthermore, the guide vanes exhibit at least essentially the same, respectively, similar transient and thermally induced deformation behaviour so that the risk of a malfunction of the first guide vane in particular due to jamming of the first guide vane and the insert parts is particularly low. This is beneficial for the functional reliability of the inventive guide apparatus and thus of the turbine so that a reliable operation of the inventive guide apparatus even over a long service life and at very high temperatures is ensured.

When the at least two insert segments are provided for forming the at least one insert part and/or the at least two vane segments are provided for forming the second guide vane this is advantageous in that the insert segments and/or the vane segments may consist of different materials. In other words, the at least one insert part, and/or the second guide vane may be manufactured from different materials.

The inventive guide apparatus may be employed for turbines of combustion engines which are configured as Diesel engines, Otto engines, Diesotto engines (Diesel-Otto engines) or other internal combustion engines. In particular, the inventive guide apparatus may be used for radial turbines where the exhaust gas flows at least essentially in the radial direction into the turbine wheel. The inventive guide apparatus may also be used for so-called mixed flow turbines where the exhaust gas flows under an angle to the axial direction and under an angle to the radial direction into the turbine wheel.

Another advantage of each of the at least partially integral configuration of at least one of the insert parts with the second guide vane is that no additional welding processes for connecting the at least one insert part with the second guide vane are required. This may prevent heat transfer and possibly distortion of the guide apparatus due to heat transfer.

In another advantageous embodiment the at least one of the insert parts and the second guide vane are each at least partially integrally formed with each other by means of a casting method. The casting method enables a quick and economical as well as integral manufacture. By means of the casting method it is in particular possible to form also relatively complex geometries of the at least one insert part and of the second guide vane quickly and economically. The second guide vane may for example be manufactured as three-dimensional blading. The first guide vane, too, may be formed as three-dimensional blading.

In another embodiment of the invention, the first guide vane is supported on at least one of the insert parts via at least one bearing element so that it is rotatable relative to the insert parts, formed separately from the first guide vane and is at least partially accommodated in an opening of the at least one of the insert parts. This leads to a particularly simple and thus to a quick and economical assembly of the first guide vane at the insert parts.

Advantageously, the second guide vane and the first guide vane and/or the second guide vane and at least one of the insert parts may be manufactured from different materials. This allows to specifically influence and adjust the deformation behavior because the different materials exhibit different behaviors in particular due to different heat expansion coefficients and temperature variations.

For a particularly simple assembly of the first guide vane at the insert parts, or at least at one of the insert parts, respectively, the opening is formed as a through-hole, wherein the bearing element may be inserted into the through-hole from a side of the at least one of the insert parts facing away from the guide vane.

Within the assembly of the guide apparatus, the first guide vane is first arranged between the insert parts, Subsequently, the bearing element is inserted into the through-hole or through the through-hole, respectively, from the side of the at least one insert part facing away from the first guide vane, and so the first guide vane is supported in a simple manner on at least one of the insert parts.

In another advantageous embodiment, the bearing element is accommodated in another opening of the first guide vane. Preferably, the bearing element is inserted into the other opening. The assembly of the first guide vane on the insert parts or on at least one of the insert parts, respectively, is effected by simply inserting the bearing element through the through-hole as well as by simply inserting the bearing element into the other hole of the first guide vane.

This support of the first guide vane on the at least one of the insert parts also prevents undesired large openings in the insert parts, which might result in undesired flow losses.

Advantageously, an anti-twist protection is provided by means of which the first guide vane is locked against a rotation relative to the bearing element. Thus, the first guide vane may be easily rotated relative to the insert parts about the axis of rotation by rotating the bearing element about the axis of rotation. In other words, the first guide vane may thereby be coupled with an actuator in a simple manner via the bearing element for rotating the first guide vane relative to the insert parts.

The anti-twist protection preferably exhibits a non-circular outer contour of the bearing element and an inner contour of the other opening which essentially corresponds to the outer contour. Thus, no separate and additional elements are necessary for securing the first guide vane in place relative to the bearing element about the axis of rotation. This keeps the number of components, the weight, the installation space requirements and the costs of the guide apparatus low.

In order to achieve a particularly anti-rotational connection of the bearing element with the first guide vane the outer contour and the inner contour each have an at least essentially wedge-shaped cross-section. This ensures an adjustment of the first guide vane about the axis of rotation relative to the insert parts over a long service life at very high temperatures so that the turbine may always be adapted at least essentially to different exhaust gas mass flows.

Another advantage of the inventive guide apparatus is that function gaps between the first guide vane and the insert parts for preventing a malfunction e. g. due to jamming of the first guide vane and the insert parts may be kept particularly small. This results in the prevention of flow losses so that at least essentially the entire exhaust gas may be deflected by means of the guide vanes and flow into the turbine wheel under aerodynamically highly efficient conditions.

Further advantages, features and details of the invention will become more readily apparent from the following description of a preferred exemplary embodiment thereof with reference to the accompanying drawings. The features and feature combinations as previously mentioned in the description as well as the features and feature combinations which will be indicated in the following description of the figures and/or which are solely illustrated in the figures are not only applicable in the respective indicated combination but also in other combinations or isolated, without deviating from the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic plan view of a guide apparatus for a turbine of an exhaust gas turbocharger of a combustion engine with an insert element comprising two insert parts, a plurality of guide vanes which are fixed relative to the insert parts and a plurality of guide vanes which are rotatable relative to the insert parts about the respective axis of rotation;

FIG. 2 shows a schematic sectional view of the guide apparatus taken along line A-A of FIG. 1;

FIG. 3 shows a schematic sectional view of a turbine of an exhaust gas turbocharger for another embodiment of the guide apparatus according to FIGS. 1 and 2;

FIG. 4 shows a schematic sectional view of another embodiment of the guide apparatus according to FIG. 3;

FIG. 5 shows a schematic sectional view of another embodiment of the guide apparatus according to FIG. 4;

FIG. 6 shows a schematic sectional view of another embodiment of the guide apparatus according to FIG. 5;

FIG. 7 shows portions of a schematic front view of the guide apparatus according to FIG. 6;

FIG. 8 shows a schematic sectional view of a turbine of an exhaust gas turbocharger with another embodiment of the guide apparatus according to FIG. 6; and

FIG. 9 shows a schematic sectional view of another embodiment of the guide apparatus according to FIG. 8.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 shows a guide apparatus 10 for a turbine (not shown in FIGS. 1 and 2) of an exhaust gas turbocharger of a combustion engine. The combustion engine is configured as e. g. a reciprocating combustion engine in the form of an Otto engine, a Diesel engine, a Diesotto engine or another combustion engine.

The turbine configured as a radial turbine comprises a turbine casing with a housing space in which a turbine wheel is least partially accommodated. The turbine wheel is rotatable about an axis of rotation relative to the turbine casing. The turbine casing comprises at least one flow duct via which exhaust gas of the combustion engine may be supplied to the turbine wheel. The exhaust gas may flow into the turbine wheel via impeller blades of the turbine wheel and drive it.

For achieving an aerodynamically efficient flow into the turbine wheel the guide apparatus 10 comprises first guide vanes 12 as well as second guide vanes 14 which are arranged in the flow duct and which may deflect the exhaust gas. By deflecting the exhaust gas it flows against the impeller blades under particularly suitable flow angles.

The guide apparatus 10 comprises an insert element 15 with a first insert part 16 and a second insert part 18. The first insert part 16 is arranged in the axial direction of the turbine opposite the second insert part 18.

As can be seen from FIG. 1, the guide vanes 12, 14 are arranged between the insert parts 16, 18. The insert parts 16, 18 as well as the second guide vanes 14 which are fixed relative to the insert parts 16, 18 are formed integrally with each other e. g. by means of a casting method. The casting method may be an MIM method (MIM—metal injection moulding), in particular a powder injection molding method. Thereby, function gaps in the axial direction between the second guide vanes 14 and the insert parts 16, 18 may be avoided, so that the exhaust gas flowing against the second guide vanes 14 is at least essentially completely deflected and flows directed into the turbine wheel and not via the function gaps past the second guide vanes 14 and undirected into turbine wheel.

The first guide vanes 12 are also arranged between the insert parts 16, 18, but are rotatable relative to the insert parts 16, 18 about respective axes of rotation 20. For this purpose, the first guide vanes 12 are rotatably supported by means of respective shafts 22 on the first insert part 16 about the axis of rotation 20 relative to the insert parts 16, 18. This means that the shafts 22 are rotatable about the axes of rotation 20 relative to the insert parts 16, 18 but are connected rotationally fixed with the first guide vanes 12.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

For supporting the first guide vanes 12 the shafts 22 are partially accommodated in respective first openings 24 of the first guide vanes 12. The shafts 22 are further accommodated in respective through-holes 26 of the first insert part 16.

Thereby, the shafts 22 penetrate the corresponding through-holes 26.

The through-holes 26 as well as the separate configuration of the shafts 22 of the first guide vanes 12 facilitate a simple and thus quick and economical assembly of the first guide vanes 12 at the insert element 15. The first guide vanes 12 are arranged between the insert parts 16, 18 so that the through-holes 26 are in alignment with the first openings 24. Subsequently the shafts 22 are inserted in a simple manner from a side 28 of the first insert part 16 facing away from the first guide vanes 12 through the through-holes 26 and inserted into the first openings 24.

The advantages of the guide apparatus 10 are in particular that the second guide vanes 14 which are fixed relative to the insert parts 16, 18 and formed integral with the insert parts 16, 18 and the first guide vanes 12 which are rotatable relative to the insert parts 16, 18 exhibit at least nearly identical transient thermally induced deformation behaviors so that the risk of malfunctions of the guide apparatus 10 in particular due to jamming of the first guide vanes 12 with the insert parts 16, 18 is particularly low. In other words, the guide apparatus 10 and thus the turbine exhibit a very high functional reliability.

Another advantage is that, due to the integral formation of the insert parts 16, 18 with the second guide vanes 14, additional joining methods, such as e. g. welding are not provided and are not necessary. This prevents heat transfer and thermally induced distortion of the guide apparatus 10. Further, the assembly of the first guide vanes 12 at the insert element 15 may be accomplished without undesired large openings of the insert parts 16, 18 which results in advantageous flow conditions for the exhaust gas.

For achieving an anti-twist protection of the first guide vanes 12 relative to the shafts 22, the shafts 22 comprise a respective outer contour in respective partial areas in which they are accommodated in the first openings 24 of the first guide vanes 12, which are formed non-circular. In other words, the respective outer contours of the shafts 22 in the partial areas which are accommodated in the first guide vanes 12 are non-circular. In the present embodiment, the respective outer contours are formed at least essentially wedge-shaped. The first guide vanes 12 comprise corresponding inner contours defining the first openings 24, which are formed as mating contours (negative contours) corresponding to the outer contours of the shafts 22. Thereby, the inner contours of the first guide vanes 12, in which the shafts 22 are partially accommodated are also formed at least essentially wedge-shaped and thus non-circular. This ensures a particularly rotationally fixed connection between the shafts 22 and the first guide vanes 12 so that the first guide vanes 12 may be rotated via the shafts 22 about the respective axes of rotation 20 relative to the insert parts 16, 18.

The second insert part 18 is also referred to as shroud element or mating contour element, respectively, because it comprises at least partially a mating contour which at least essentially corresponds to an outer contour of the turbine wheel and which covers or shrouds, respectively, the turbine wheel in particular radially towards the outside. The exhaust gas driving the turbine wheel may therefore be aerodynamically efficiently deflected from the turbine wheel and introduced into a turbine outlet. The second insert part 18 is formed at least essentially annular.

The first insert part 16 is also referred to as control ring because it is formed at least essentially annular and because the first guide vanes 12 which are movable relative to the den insert parts 16, 18 act as flow control elements. By means of the first guide vane 12 an effective flow cross-section of the turbine, via which the exhaust gas is supplied to the turbine wheel, may be adjusted, i. e. fluidly opened or restricted, respectively.

In FIG. 3, portions of the turbine casing of the turbine, which are identified by the numeral 30 are indicated. According to FIG. 3, the insert parts 16, 18 and the second guide vanes 14 are formed separately from each other but are firmly interconnected. To this end, the second guide vanes 14 are welded to the first insert part 16 under the formation of respective welds 32 and are welded to the second insert part 18 under the formation of respective further welds 34.

The second guide vanes 14 comprise respective pins 36 which are at least partially accommodated in second openings 38 formed as through-holes of the second insert part 18.

In order to prevent or at least minimize so-called secondary flow losses a sealing element 40 is provided which is supported on the turbine casing 30, on the one hand, and on the second insert part 18, on the other hand. By means of the sealing element 40 the second insert part 18 is sealed against the turbine casing 30 so that the exhaust gas at least essentially cannot flow through a space between the turbine casing 30 and the second insert part 18 and thus past the guide apparatus 10 but is at least essentially completely supplied to the turbine wheel via the guide vanes 12, 14 and thereby aerodynamically efficiently deflected or diverted, respectively. In the present case, the second insert part 18 comprises a reception feature in the form of an annular groove 41 in which the sealing element 40 is partially accommodated.

In the guide apparatus 10 according to FIG. 4, the second guide vanes 14 are also welded to the insert parts 16, 18 under the formation of the welds 32, 34. The second guide vanes 14 comprise further pins 42 which are at least partially accommodated in respective third openings 44 of the first insert parts 16. Here, the third openings 44 are also formed as through-holes.

According to FIG. 5, the second guide vanes 14 and the first insert part 16 are formed integrally with each other e. g. by means of a casting method. For connecting the second guide vanes 14 and the first insert part 16 with the second insert part 18 it is provided that the second guide vanes 14 are at least partially accommodated in the second openings 38 via their pins 36 and under the formation of the welds 34 are welded and thus materially bonded to the second insert part 18.

When viewing FIGS. 6 and 7, it can be seen that the second insert part 18 of the guide apparatus 10 consists of a first insert segment 46 and a second insert segment 48 wherein in the present case the insert segments 46, 48 are interconnected by means of a positive plug-in connection. Furthermore, the second guide vanes 14, the first insert part 16 and the first insert segment 46 are formed integrally with each other. This means that the second insert part 18 is partially formed integrally with the second guide vanes 14 and the first insert part 16.

According to FIG. 8, the second guide vanes 14 and the first insert part 16 are integrally formed with each other and separately from the second insert part 18. Each of the second guide vanes 14 comprises a plurality, in the present case, two pins 36 which are at least partially accommodated in corresponding second openings 38 which are formed as through-holes. The second guide vanes 14 are welded to the second insert part 18 under the formation of welds 34.

FIG. 9 shows another embodiment of the guide apparatus 10, wherein the pins 36, 42 comprise respective chamfers 50 so that the pins 36, 42 are partially formed conical or truncated, respectively. Here, the chamfers 50 may serve as an insertion aid so that the pins 36, 42 may be inserted without tilting into the opening 38, 44 easily and thus quickly and economically and may subsequently be welded under the formation of the welds 32, 34. 

What is claimed is:
 1. A guide apparatus (10) for a turbine of an exhaust gas turbocharger with an insert element (15) comprising a first insert part (16) and second insert part (18) arranged opposite the first insert part (16) and with at least one first guide vane (12) for deflecting exhaust gas flowing through the turbine arranged between the insert parts (16, 18) and rotatably supported on at least one of the insert parts (16, 18) so as to be rotatable about an axis of rotation (20) relative to the insert parts (16, 18), and at least one second guide vane (14) for deflecting the exhaust gas mounted immovably between the insert parts (16, 18).
 2. The guide apparatus (10) according to claim 1, wherein at least one of the first and second insert parts (16, 18) and the second guide vane (14) are at least partially integrally formed with one another.
 3. The guide apparatus (10) according to claim 2, wherein the at least one of the first and second insert part (16, 18) and the second guide vane (14) are formed jointly cast.
 4. The guide apparatus (10) according to claim 1, wherein the first guide vane (12) is supported via at least one bearing element (22) which is rotatable about the axis of rotation (20) relative to the insert parts (16, 18), is separately formed from the first guide vane (12) and at least partially accommodated in an opening (26) of the at least one of the insert parts (16, 18).
 5. The guide apparatus (10) according to claim 4, wherein the opening (24) is formed as through-hole (26), so that the bearing element (22) can be inserted into the through-hole (26) from a side (28) of the at least one of the insert parts (16, 18) facing away from the first guide vane (12).
 6. The guide apparatus (10) according to claim 4, wherein the bearing element (22) is accommodated also in an opening (24) of the first guide vane (12).
 7. The guide apparatus (10) according to claim 6, wherein an anti-twist protection is provided by means of which the first guide vane (12) is secured against a rotation relative to the bearing element (22).
 8. The guide apparatus (10) according to claim 7, wherein the anti-twist protection comprises a non-circular outer contour of the bearing element (22) and an inner contour of the first guide vane (12) essentially corresponding with the outer contour and defining the other opening (24).
 9. The guide apparatus (10) according to claim 8, wherein the outer contour and the inner contour each comprise an at least essentially wedge-shaped cross-section.
 10. A turbine for an exhaust gas turbocharger with a turbine casing (30) in which a guide apparatus (10) according to claim 1 is arranged. 